Segregated and alternately stacked donor/acceptor nanodomains in tubular morphology tailored with zinc porphyrin-C60 amphiphilic dyads: clear geometrical effects on photoconduction.

Amphiphilic zinc porphyrin (P(Zn); electron donor, D)-fullerene (C(60); electron acceptor, A) dyads 2 and 3, bearing an identical hydrophilic wedge with triethylene glycol chains but different linkers between the P(Zn) and C(60) units, self-assemble into nanotubes with essentially different dimensional and geometrical features from one another. The nanotube from dyad 2 with an ester linker consists of a bilayer wall formed with coaxially segregated D and A nanodomains along the tube axis (coaxial D-A heterojunction), thereby displaying explicit photoconductivity with ambipolar carrier transport properties. In contrast, the nanotube from dyad 3 with a rigid arylacetylene linker consists of a monolayer wall with an alternate geometry of D/A stacking, resulting in poor photoconducting outputs. Such a geometrical difference also significantly affects the photovoltaic properties.